In recent years, several functional peptides (PTD: protein transduction domain) having an ability to penetrate into a cell have been identified, and attempts to develop PTD as an effective DDS (drug delivery system) carrier for percutaneous or permucosal absorption or brain delivery of a nucleic acid or a protein have been noticed. For example, the peptide/protein has been tried to be introduced into the cell using peptides derived from HIV-1 Tat protein in Patent document 1. However, these PTD are poor in cell specificity and insufficient in introducing efficiency of proteins into the cell. Thus, it is essential to improve existing PTD and identify novel PTD. From this point of view, a cationic amino acid introduction body has been produced worldwide by peptide synthesis with trials and errors for the purposes of making analogues and enhancing an adsorption to the cell based on conformational analyses of PTD. However, diversity of peptides capable of being synthesized is limited, and no PTD superior to the TAT peptide has been found yet.    Patent document 1: Unexamined Japanese Application H10-33186.